This invention relates to measurement apparatus and, in particular, to apparatus for measuring length, surface area, volume and the like of three dimensional objects.
In many different applications it is desirable to be able to accurately measure the length, surface area or volume, for example, of an object or enclosure. In particular, for example, it is often desirable to be able to estimate the quantity of paint or wallpaper one might require to decorate a room, or the number of tiles which may be required to cover a roof. However, it is often impractical, difficult or simply impossible to measure the required dimension by hand using a tape measure or the like.
U.S. Pat. No. 4,730,190 describes a hand-held measuring device which operates effectively as a remote tape measure. Thus, the user measures the three dimensions of, for example, a room and the device multiplies the three dimensions to give the volume of the room.
However, this type of device is time-consuming to use and prone to error. Further, it is really only suitable for giving accurate volume measurements of substantially uniform right-angled areas. It would not give an accurate measurement for an area having curved or irregular sides, for example, and straight line approximations are not accurate enough for many applications. Further, the area to be measured must be accessible to the user in order for the relevant lengths to be measured. Thus, for example, it would be difficult for a user to measure the volume or surface area of a roof without having to climb up on the roof to take the relevant measurements.
We have now devised an arrangement which overcomes the problems outlined above.
In accordance with the present invention, there is provided a measurement apparatus for measuring at least one parameter of an object or area, the measurement apparatus comprising one or more imaging and display devices for creating a three-dimensional map and displaying an image of said object or area, mapping apparatus for mapping a virtual shape onto said image and substantially matching said shape to said object or area, the measurement apparatus being adapted to determine from said image at least one parameter of said object or area, said parameter comprising at least one of a length, surface area or volume of said object or area.
It will be appreciated that the shape matching takes place in a two-dimensional image space, and the apparatus can create any (selected or otherwise) two-dimensional perspective from the three-dimensional map, thereby permitting a user to choose the perspective in which matching takes place, which may be particularly important in the case where important matching points cannot be seen from a particular perspective.
The present invention also extends to a method of measuring an object or area, the method comprising the steps of creating a three-dimensional map and displaying an image of an object or area to be measured, mapping a virtual shape onto said image, substantially matching said virtual shape to said object or area being measured, and determining at least one of a length, surface area or volume of said object or area.
The apparatus preferably includes means for marking or otherwise selecting the object or area to be measured within an image, by defining an outline of the shape of said object or area. The apparatus then preferably creates a virtual shape which substantially matches the outline. The apparatus beneficially includes means for permitting the user to alter one or more of the size, angle or pitch of the virtual shape.
Thus, the present invention employs an imaging technique which can recover depth as well as azimuth and elevation. The apparatus of the present invention is particularly (but not exclusively) useful for quickly and accurately estimating quantities of, for example, paint, wallpaper, tiles or carpet required for a particular area. In fact, the apparatus may include means for providing an estimate of the amount of such materials which are required. It may also include means for taking into account standard material widths, lengths, volumes, etc, when estimating the quantities of a material required to be obtained.